An Analysis Of Clinical Features And Pathology In40Patients With Dysferlinopathy

Objective: Mutations in the dysferlin gene (DYSF) lead to a complete orpartial absence of the dysferlin protein in skeletal muscles and are at the originof dysferlinopathies, a heterogeneous group of rare autosomal recessiveinherited neuromuscular disorders. So far, the classifications of thedysferlinopathies mainly have included limb-girdle muscular dystrophy2B(LGMD2B) with predominantly proximal weakness, Miyoshi myopathy (MM)with calf muscle weakness and atrophy, and distal myopathy with anteriortibial onset (DMAT) with tibialis muscle atrophy. To analyze the clinicalmanifestations, features of the biopsy of skeletal muscle with histochemistryand immunohistochemistry staining of40patients with dysferlinopathy andinvestigate its clinical, pathological diagnostic value and possible pathologypathogenesis.Methods:1.The clinical data of40patients who were diagnoseddysferlinopathy from2004to2011in the department of neuromusculardisease of the Third Hospital of Hebei Medical University had been collected.Following the diagnostic criteria:1)symptoms generally appear at the end ofchildhood or adulthood;2)slowly progressive weakness and atrophy ofproximal muscle, gastrocnemius or tibialis anterior muscle;3)creatine kinaseincreased in all patients; eletromyogram (EMG) showed myogenic lesion;4)biopsied muscle offered myodystrophy change: muscle fiber diameter varies,active degenerating, necrosis and regenerating, connective tissue moderatelyor markedly increased, except metabolic myopathy and others. Anti-dysferlinmonoclonal antibody immunohistochemical stain showed absent or markedlydecreased on sarcolemma of fibers.2. Reperform histochemical stains andimmunohistochemical stains on biopsied muscle specimen and pathologicalanalysis.3. Analysis electronmicroscopy of seven dysferlinopathy patients’muscles.4. The clinical data, features of the biopsied skeletal musclewith histochemistry, immunohistochemistry staining and ultrastructurefeatures of40patients with dysferlinopathy were analyzed.Results:1Clinical characteristics of dysferlinopathy:Chronic progressive weakness and wasting were the general clinicalmanifestations. In our study, it was divided into three phenotypes according tothe involved muscles of dysferlinopathy:27cases with proximal muscle(LGMD2B),12cases with the gastrocenemius (MM),1case with the tibialisanterior muscle (DMAT).27LGMD2B patients include15males and12females. The age of onset altered from8to56years and the mean age was22years. The course of disease ranged from2months to46years, and4patientshad positive family history. The onset of LGMD2B occurs in early adulthood.Muscle atrophy is most dominant in proximal muscles, especially the lowerlimb muscles. As advances, distal muscles are involved.12MM patientsinclude7males and5females. The age of onset altered from14to37yearsand the mean age was20.5years. The course of disease ranged from3monthsto15years, and2patients had positive family history. The onset of MMoccurs with the distal lower limb muscles. As advances, muscle atrophyprogresses to the thigh and hip muscles. There is1female DMAT patientwithout positive history, and the onset age is43years old. The course is14years. The onset of DMAT occurs with the tibialis anterior muscles weaknessand atrophy.2The laboratory features of dysferlinopathy:The serum creatine kinase levels all had a rise in different: it moderatelyor markedly increased in39patients, but only1case slightly increased.All the patients showed myogenic lesions in electrophysiologic study.12patients underwent skeletal muscle MRI. Proximal muscle wasinvolved in4cases; gastrocnemius muscle was mainly involved in7cases;and anterior tibial muscle initially was involved in1case.3The pathological analysis of muscle biopsy under light microscopy: All40cases showed active muscle fiber degeneration, necrosis andregeneration on muscle pathology. Connective tissues were proliferated andinflammatory cells infiltrated in endomysium, perimysium and perivascularsites of16patients. Immunohistochemical staining with anti-dysferlinmonoclonal antibody identified the deficiency of dysferlin in the sarcolemmaof30cases with dysferlinopathy, and dysferlin was severely reduced in10cases. In anti-dystrophin-N,-C,-R and anti-Sarcoglycan-α、-β、-γ、-δmonoclonal antibodies, dystrophin and sarcoglycan are normal.4Seven cases were seen under electronmicroscopy of muscle fiberstructural characteristics:The phased destructioin of the muscle fiber membrane continuity causingto thicked or thinned; some areas showed Many papillary projections wereoriented either parallel or perpendicular to the sarcolemma; small vesiclesclustered in sarcolemma, sarcolemma defects and papillary projections;basement membrane thicked; mitochondrial vacuolization and lysosomalmyeloid changed in the cytoplasm.Conclusion:1Progressive weakness and wasting of skeletal muscle are the clinicalmanifestations of dysferlinopathy. The early involved muscles determine theclinical phenotype of dysferlinopathy. High serum creatine kinase levels showthat dysferlinopathy is a membrane protein null disease.2Muscle MRI of lower limbs may reflect the involved muscles, whichis essential for clinical phenotypes and selecting muscle biopsy. Thepathological characters of dysferlinopathy are changes of muscular dystrophy.3The deficiency or severely decreased dysferlin on the sarcolemma inimmunohistochemical staining with anti-dysferlin monoclonal antibody isimportant information for diagnosing dysferlinoapthy. Inflammatory cellularinfiltration is relatively common in biopsied muscles of many dysferlinopathypatients, and dysferlinopathy needs to be differentiated from inflammatorymyopathies.4Ultrastructure changes include: the phased destructioin of the muscle fiber membrane, vesicles aggregation, basement membrane thickening andlysosomal aggregation in the cytoplasm, which prompt that plasma membraneinjury-repair may be an important event in the pathogenesis ofdysferlinopathy.